>"the person performs work that is outside the usual course of the hiring entity’s business" is the tricky one, but I think it more has to do of what you explain your business to be. If you are running a SaaS platform and enter into a contract with someone who provides software development expertise the relationship between your business and the contractor is different.

This argument seems too general. One way of looking at Uber is that it's a taxi service. Therefore, Uber and an Uber drivers are engaged in the same line of business. Another way of looking at Uber is that it's a platform to connect drivers and passengers. Therefore, Uber and Uber drivers are engaged in different kinds of business.

If you need to explain what your business is in a particular way, then you're on thin ice.